Hygrometer for humidifying and air-moistening apparatus.



-PATENTED NOV. 19, 1907.

y y s. W. CRAMBR. '#IHYGROMETER PQR HUMIDIPYING AND AIR MOISTENING APPARATUS.

EPPLIOATION FILED JULY 2s, 190e.

3 SHEETS-SHEET 1 Y IUD INVENTOR Allamey No. 871,163.; PATENTEDNOV. 19, 190? S. W. CRAMBR.

HYGRMETBR FOR HUMDIPYING AND AIRYMOISTENING APPARATUS.

' APPLIoATIoN Hmm JULY z3, 190s.-

a sEBTs-SHBBT s.

BY .dye .w

UNITED sTATEs PATENT oEEioE.

STUART w. ORAMEE, or cHAnLoTTE, NORTH CAROLINA.

HYGBOMETER non HUMIDIFYING ANDAIR-MoIs'rENIN-Gl APPARATUS.

L Specicationof Letters Patent.

Patented Nov. 19, 1907. i

Application filed July 23, 1906. Serial No. 327.428.

T o all whomfitmafy concern,- l l f Be it known that I, STUART W. CRAMER,a citizen of the United States, residingat Charlotte, in the 'county ofv Mecklenburg and Stateof North Carolina, have invented certainnew and `useful Improvements in Hyrometers for .Humidifyin' and Air-Moisten- .1 n` Apparatus; and I do` ereby-.declare the fo owing'to be a full, clear, and exact description 4of. the inventiomsuch as will enable vothers skilled in the art to which it appertains to make'and use the same. f

My inventionrelates to instruments .for inl dicat'ing thedegree of-moisture in the atmos- .15' phe're, and consists in certain im rov'ements Y' in construction, 'which -willbe -y disclosed l in the following specification and claims.

"In, .the j accompanying drawings, ,which form part of this specificationz-Figure 1 \hygrometer. Fig. 2 a vertical transverse section .of the same. Fig. 31 a front elevaf tion, showing` amodied form of hygrometer.

represents a front elevation of my improved Fig. 1 4 .a'.ver\ticalseetion partly in side eleva-.a

2 5: tion showing the hygrometer applied to one ofthespray type of huinidiiiers, and Fig.`5 a

like view` showing the liygrometer` applied tol or evaporative type one of thesaturated air 'i -30 A' The qantityof moisture in the air under different conditions of temperature and' at different 1percentages of saturation, is usually measure yby'two entirely` separate anddis- A tinct devices. The most .convenient ,device "35 would'be .the type oll hygromete whicl, for

- may esigna e .asA

wantl lof', a `better term, thernechanical ty v e inthis type the senf siti've` member of t 1e instrument is usually of vegetable or .animal origin, the operationl 40 y of whichrintheresence of varying amounts of moisture in t e atmosphere causes movementjof the indicating means of the instrument.- v,The sensitive substance 'generally contracts `or expands, or twist-s `or 'untwis`t`s, .or otherwise changes its form or dimension, which motion in turn bysuitable mechanism is communicated to the indicating means and A translated generally into the motion of a needle on `a graduated dial. This type of instru/- -ment is the most convenient of all devices,

' and requires practically no attention whatf` everl after being once set. Were its accuracyequal lto its convenience, it would be the only device` adopted. y Unfortunately, however, it is utterly untrustworthy on account of two'di'ficulties inherent in its type. The

one being thatfhumidity'ailects the instruments to a different degree at different temperatures; and the other being the susccpti- )ility of the surface pores of the sensitive substances to being choked or filled up by the indications to become both sluggish and erratic. The second type of instrument referred to, and the one which is recognized as the standard for that purpose, is ot the well dust, lint, etc., a thin coating of which causes known wet and'dry bulb thermometer type.

This ty e may be further sub-divided as follows: ne (and the one best known to the public) which, in order to secure accurate readings, it is necessary to safeguard it from drafts; the makers of such instruments furnish printed precautions with them, stating that they should beexposed in the shade, free from air currents, and that the covering of the wet bulb must be very thin, and that itmust be kept. constantly moist, and that the water used must be distilled water to minimize ,the deposits on the wicking which tend to lessen the absorbentpower of the `material whereby the wet bulb is ke t moist.

This'ty e of instrumentis ada tec and de,-

signed or continuous usage, an( is intended 4to lndicatefat all times'and be ready for inspection at anyA moment. The other subclass is ythe sling, or whirled, psychrometer, the instrument in use by observers at all stal tions of the U. S. Weather Bureau; in this type of instrument, satisfactory results cannot be obtained from observations in relastrong current is absolutely necessary'to accuracy. This `type ot' linstrument is lundicatingfeature of tghe one type and the averaging of conditions in the ther type, combine( with the'. further and radical change in construction `of doing away with the muslin cover or wicking on the wet bulb entirely.

vtively stagnant air, but, on the contrary, a n

1054 'hygrometers, retaining the continuous inture of the wet bulb is the same" as the 'temperature of the water on the .surrounding the bulb, that the wet bulb* thermometer simply indicates that tem-I perature.. Therefore, it only. remains to wicking or muslin covering. Repeated ob-v Humidity, with a wet and I.dry bulb type I or exposedwet bulb @extended and slightlyA evince i of hygrometer, may be saidV to 'be measured bent.

byv the lcooling .eifect of -the evaporative power of the atmosphere at di'erent tem- 'peratures and different'percent'ages' o'f satura'tion. It is obvious that as the temperameasure with any 4`kind lof ather'mometer the temperature of water-similarly cooled tothe point of saturation of the atmosphere to obtain the 'equivalent of a wetbulb read-g ing-from whence it lis evident that .'.under proper conditions the usual Wetbulb Ycovering or wicking, as it isgenerally termed, can be omitted. These proper' conditions reproper precautions are taken vto' insure jthat the reductionlof'the temperature'in the act of saturation th/at air is communicated Without appreciable' loss to the bulb of the 'indieating thermometer. In practice it is found thatthis reduction oftemperatuie can b e' accomplished in either 'one of-three dierent Ways-,- and `satisfactorily vapplied to veffect .the Aproper depression'of what'rnay still be termed the wet bulb. (1) By saturating the-air, and immediately directing it against the'bulbof a ther.- mometer. such a case, it i-s desirable to have the air, if possible, slightly surcharged withvmoisture. (2) By directing a finely divided spray of water of high velocity against the-bulb, carryingwith it sufficient air to accomplish the necessary evaporation'. (3) By directing a fine sprayr'lipon 'the bulb, orcovering the bulb with'a thin-film of water, and Adirecting an air current uponv the bulb at the same time.'v f

methods of cooling the wetbulb thermometer, and dispensing with'the use of the servations with certified thermometers show that the methods of cooling the vwet bulb given above are as accurate as readings-can' be made with even. a sling psychrometer. In order to "insur'eextreme precislon, 1t 1s of course necessary to subject the .bulb that'.l

is to beused as, the dry bulb to the s-ame velocity of the airasthat used'to obtain the"v cooling eect' on the one .to be used for thel wet bulb. i

Reference being had'to the'drawingsand the designating characters thereon, the' numeral 1 indicates the board-on which "the apparatus is supported. j e i 2 isthe dry bulb thermometer of'the usual form.A

3 is thej wet bulb thermometerconstructed according to the Sixe form,- with the naked In order to insure saturation ,in

into which the wetbulb leg of the Wet-bulb thermometer projects. It is supported by rings 6', attached -to -a bracket 7, screwed to the board Underneath-the casing4 5 isa funnel -shaped'receptacle 8, provided Vwith aV drip pipe 9, which receives the Water and conveys'itto a suitable receptacle, not shownll. vThis `vfu'nnel is. open on' the back and theside's at 10'to allow the spray and air passing through the casing to escape and dissipate itself into the atmosphere.A

lllis aspray. head, either1 ofthe ordinary 'iatomiz'er type or Water underpressure, that is designedto break up into a fine spray,.12, moreor less cone shaped-thatisto be pro-v i jected thl'pugh'the casing 5.

ferred to are necessarily .those in which the 13. is the liquid supply pipe'for the A'spray head. l

leg of e thermometer by anGOlk-.15Land of-this tube, 1.4,.is to keep thetemperature 5 represents a -casing open at both' ends y llis a glass insulating. tube tted to .the

'extend d 'withinthe casing. Thefunction of the water as itjissuesfrom the spray Ahead I '11, from affecting the temperature of the thermometer -before the spray issuing from thespray head has had ytime'to be cooled' vdown to what' may betermed the wet bulbV temperature yby the evaporation of the'flne articles of moisture comprising the spray,

when commingled. with the-"currentsof air I' 16,l induced/by thejet of A'spray' and 4driven through the casing 5.*

, The operation of this lnstrument hasv -already been indicated in the description. It is only-necessary to remark, therefore, that the casing 5, can advantageously b e'made of glass, so that .the working of the instrument can be observedat any or all times. The

length of the casing 5, is' governed by'fthe force :and the amount'of spray that itis de- Iv propose-'utilizing each of these'v three:r

signed to use, bearing in mind thefact thatV the bulb. 4, vmust beat such a distance from the spray' head1.l,'lthat the current of air and fine spray passing through the 'chamberwil-l have been lowered to .what I have already' termed the wet bulb temperature.y

.' In Fig. 3l have shown-a modification of an' instrument constructed along these ygeneral lines. 17 represents a water supply that may be supported on the front or'back of the hy-' .groin'eter board `1, that supplies va device bulb 4. -20 is .a propeller fan `of.'the well known type, driven by an electric. motor 20',

'1 20 ,sight feed lubricator is of the well known rubber tube 19, that drips waterfslowly, drop f after drop, 'which spreads itselfv in a fine lm which is clamped'on to the side of the board .I 1, by a support 21. Itdrives currents of air .41'6 past the' dry bulb thermometer, Zand on 1 past the bulb lof the wet bulb thermometer, l through the humidifier, -a by no means unuoyerwhich the thin film of water is tricklingf The evaporation of the .thin film of water by' the air blast reduces the temperature of the type ofjspray humidifier.

wet bulb thermo-meter to its proper point.

'22 is a drip cup provided with a waste connection 23, to take away the superfluous water. ln this type of instrument it is particularly necessary to be careful that the thin film of water is so small in quantity th at the temperature ofthe water will not affect the' temperatureof the wet bulb.

In Fig-4 l have shown the` application of the lthermometers following this' general-line of construction', tothe usual and well know-n The humidifier easing is indicated by the numeral 24. The dry bulb thermometer in this case, it will be noticed, is indicated Vby the numeral 25. The currents of air are shown by arrows indicated by the numeral '16, as l etofore, and the spray by the nuneral 12. It is thusI easily seen that the diaft ofA air passing the dry bulb, 215, causes the dry bulb thernn neter to .indicate the temperature of the air going through the apparatus; and the temperature indicated bythe naked or exposed wet bulb 4, in the path of and'exposed to the spray and cooled air shows the properwet bulb temperature in the other thermometer.

Fig. as already stated, shows the evaporative type of humidifier 26. This one is of the type that is filled with internal expanded surfaces 27, over the surface of which the water 28, issues from a number of perforations," the water entering through the supplypipe 29. Saturated air issues from the apparatus betweenthecasing and the collecting pan 3 of the humidier. The bulb of the dry-bulb thermometer 2 is ih the path of and exposed to the air entering lthe casing 26, and the naked or exposed bulb 4 of the 'wet bulb thermometer 3, is in the path of and exposed.

tothe saturated airin its escape from the lower end of-the humidifier. lt is obvious, therefore, from the foregoing description that thermometers applied'to this type of humidifier will also indicate correctly the wet and dry bulb readings for showing the relative humidity of the atmosphere that enters the casing,-in other words, which is supposed to represent the average conditions el. the room.

In commenting upon these lvarious type of apparatus, it is true the average humidifier is cut off occasionally, and in that evem the instrument will be out of operation, for the thermometers will indicate correctly only when the humidiiiers are running. i should explain, therefore, that it my purpose not to use the application of my invention 'to indicate the humidity of the air the room, but merely to indicate the con tien of the air voutside the room wl! b.

`sual practice in ventilation. The readings ofthe thermometers attached to such a humidifier, therefore, would show the humidity of the incoming outside air--information that it is decidedly advantageous to have in the art of air conditioning so far as relates not only t'o humidity but to ventilation and temperature.

land dry bulb thermometer instruments.

It is obvious that the kind of thermometers used is immaterial; they may be of theusual glass bulb mercury type, or of any other type of whatsoever .kind or shape, this method of cooling the`wet bulb particularly lending itself to large or unusual kinds of thermometers.

It is evident that the construction heretofore described andillustrated can be modified and varied lin a number of wayswithout -ination with means for saturating a current of air which is applied to the surface of said uncovered bulb, and means for producing the current of air.

2. A hygrotneter comprising a dry bulb thermometer and a wet bulb thermometer, the latter thermometer having an uncovered bulb; in combination with means for producing and `supplying a finely 'attenuated spray of water to a current of air of requisite psyehrometrie wet bulb temperature and to which currentof air said wet bulb is exposed, and means for producing the current of air.

3. ln an instrument for indicating humidity, a dry bulb thermometer and ufwct bulb thermometer, means for supplying a finely attemmted spray oi' water, and means for commingliug air with said spray and directing said eommingled air and spray upon said wet bulb.

l. in. a immidilier, a dry bulb thermometer and a wel bulb inhormometer, means for across the su se of the bulb of the dry bulb l, e

and

tiurmomeler, means for din The'. principal use to which l propose putting my'invention therefore is,

ting the air as it enters the humiiili'lier .43. l @ames A5 humidifier, and the bulb of thei wet bulb In testimony 'whereof I affix K'signalture,v

5. 'In a, humidifier, a dry b l'ilb'thermom humidifier, and a Wet'bulb thermometer havter'and -a Wet bulb thermometer, the bulblof ing the 'bulb thereof arranged' in the pjthof thedry bulb thermometer arranged in the and exposed to the moistened air issuing;

path of and exposed to theair entering the. from the humidier.'

thermometer arranged in the path o'fand in presence of two witnesses ,exposed to the moistened'and coole-d air issu- Y 1 ing from the humidifier. Y STUART, W'ORAMER'- 6. In a humidier, a dry bulb thermomef Witnesses: 10 ter having the bulb thereof'arran'ged in the -D. C. REINOHL,

path.v of end 'exposed to the air entering the W. PARKER RENOHL; 

